"Patients' and Families' Psychological Response to HAT (PRHAT)" constitutes an independent project complementary to the ongoing NIH clinical trial "Home Automatic External Defibrillator Trial (HAT)". PRHAT will investigate long-term changes in anxiety and depression and the moderating influences of social support and family coping skills on these changes for post MI patients and their spouses/companions after training to respond to sudden cardiac arrest (SCA). Previous research has shown that training family members in CPR increases anxiety and depression in the post MI patient and the trained family member. Anxiety and depression in post-MI patients is associated with SCA. PRHAT is the first study to examine the long-term psychological responses (anxiety and depression) for post myocardial infarction (MI) patients and their spouse/companions to SCA training. It will compare the outcomes of standard lay training (call EMS/CPR) and standard lay training plus the use of a home automatic external defibrillator (AED) and examine the moderating effects of social support and family coping skills on anxiety and depression in both patients and the spouses/companions. At least 200,000 SCAs occur in the United States each year, 70% take place at home and are witnessed. Survival falls 10% per minute over the first ten minutes, therefore immediate, effective response is critical. The central hypothesis of HAT is that providing an AED for home use will improve survival beyond that achieved from the typical lay response to SCA. PRHAT will recruit 440 of the 7,000 patient-spouse/companion pairs enrolled in HAT. PRHAT will assess anxiety, depression, social support and family coping at study entry, and at one month, one year, and two-year follow ups for patients and spouses. The tools administered in PRHAT will provide essential information to complement and extend the impact of the HAT and while minimizing participant burden. The HAT will provide the infrastructure for sites, recruitment and screening of subjects, standardized CPR video instruction, the AED devices, quality of life assessment, and facilitation of follow up of post MI patients and their spouses/companions. HAT clinical trial will began recruiting participants on 10/01/02 and continue to 3/01/05. Beginning PRHAT on 7/01/03 allows ample time for simultaneous recruitment into HAT/PRHAT. PRHAT data will identify patients and families who are vulnerable to becoming anxious and depressed.